The Marburg virus (MARV) is an African filovirus that causes a deadly hemorrhagic fever in humans, with up to 90% mortality. Because this virus is very stable, infectious by aerosol, and can be produced in large quantities, it poses a serious threat to our nation and to its armed forces, either as a naturally occurring pathogen or as a potential biological weapon in the hands of our adversaries. Currently, there is no approved treatment or vaccine available against MARV infection. We propose to develop an effective vaccine for protection against infections by three known strains of MARV: Ci67, Musoke and Ravn. We hypothesize that high levels of MARV antigen expression in vaccinated tissues mediated by MARV vaccine vector will mimic the antigen-presenting processes of a natural virus infection and will induce a strong and long-lasting protective immune response against MARV infection. In addition, MARV glycoproteins (GP) expressed from a cAdVax vector in cells will form the natural confirmation of the target epitopes and will be essential to induce neutralizing antibody responses against the natural viral proteins, and that expressing the GPs of three MARV strains in addition to a single NP in cAdVax-based vaccines will elicit both humoral and cell-mediated immune responses against the three MARV strains. Based on this hypothesis, we have inserted genes from the three MARV strains into a novel, replication-defective, complex recombinant adenovirus vaccine (cAdVax) vector. In preliminary studies, this vaccine platform induced potent antibody and cytotoxic T lymphocyte (CTL) responses as well as protective immunity against lethal challenge by all three MARV strains both in a small animal model and in non-human primates. Here, we propose to conduct all studies necessary to fulfill FDA/CBER requirements in order to move the vaccine product into human clinical trials.